System Information
Windows 7 64, HD 5770

Blender Version
Broken: 9e963ae (2.72b release) + 5e0e175

Short description of error
I think 2D Curves dont react properly after Switch Direction (W) when it comes to Curve Deform, the mesh doesnt turn around.
Therefore its impossible to use 2D Curves for setups that work counterclockwise.
(Note: the presets for new Curve circles always point clockwise)

I am aware that this smells a lot like >works as intended< due to the fact that direction arrows are missing in 2D, but
it seems that there is something fishy going on after switching the direction of a 2D curve = the deformed mesh still moves 120° along the default curve.
So i thought this is more a limitation because of a bug.

Exact steps for others to reproduce the error
{F121936}

• Add any Curve Circle.
• Add a Monkeyhead.
  • Give it a Curve modifier: use the Circle.

• Go to Curves Editmode
  • Select all (A) and Switch Direction (W)

The monkeys face will turn to the outside, as well as the deformation direction along the curve = positive X axes follows counterclockwise.

• Go to Curves settings in Properties window and select 2D.

Problem: Direction and monkeys deformation are clockwise again.
This issue blocks specific setups that should use the 2D curve (Fill+Bevel/etc) in combination to its deform ability.

Something else that i noticed during the report:
Textobjects numbers and letters seem to have random normal-direction when deformed on a curve.
You can see this in my file.